Coordination Chemistry Department of Chemistry School of Science Beijing Institute of Technology Hui Li
Questions 1: What are the four fundamental branches of chemistry? inorganic chemistry organic chemistry analytical chemistry physical chemistry
Active research is performed in border areas towards organic chemistry, catalysis, materials, biochemistry and physics.
Chapter 1. Introduction Chapter 2. The Electronic Structure Theory of Coordination Compound Chapter 3. Electronic Spectra of Coordination Compound Chapter 4. Structure and Properties of Coordination Compound Chapter 5. Kinetics and Mechanism of Reactions of Coordination Compound
Textbook: 《配位化学（双语版）(Bilingual)》，李晖编著，化学工业出版社（2006年2月版）。 • References: • “Metals and Ligands Reactivity” - Constable - VCH Publishers. • “Advanced Inorganic Chemistry” - Cotton, Wilkinson, Murillo and Bochmann - Wiley. • “Inorganic Chemistry, Principles of Structure and Reactivity” - Huheey, Keiter and Keiter - Harper Collins College Publishers. • “配位化合物的结构和性质”，游效曾 编著， 科学出版社（1992年2月）。
Chapter 1 Introduction
The Origin of Coordination Chemistry 1. Early Coordination Compounds 2. Modern Coordination Chemistry
Conductivities of CoCl3·6NH3 were measured when the compounds were dissolved in water. AgNO3(aq) + Cl−(aq) −→ AgCl(s) + NO3−(aq)
Isomers are deﬁned here as compounds that have the same numbers and types of chemical bonds but differ in the spatial arrangements of those bonds.
Alfred Werner (1866-1919) was appointed at the University of Zurich to teach organic chemistry. In fact, he was very interested in inorganic chemistry and found many problems to disturb the inorganic chemists.
Two types of valence: a primary valenceorionizable, valence corresponded to what we call today theoxidation state; for cobalt, it is the 3+ state. a secondary valenceismore commonly calledthe coordination number(ﬁxed geometric positions in space).
Some chloride ionsmust dodouble dutyand help satisfy the both of primary valence and secondary valence.
Please distinguish the two concepts of“oxidation number” and “coordination number”.
Thegeometry of the secondary valence The number ofactualversus predictedisomers for three different geometries
Proposed structure of cobalt ammonia complexes from number of ionized chloride solid color ionized Cl- complex formula CoCl36NH3Yellow [Co(NH3)6]Cl3 CoCl35NH3 Purple [Co(NH3)5Cl]Cl2 CoCl34NH3Green trans-[Co(NH3)4Cl2]Cl CoCl34NH3Violet cis-[Co(NH3)4Cl2]Cl
Again, checking some interesting compounds: [Co(en)3]2+ [Co(en)2ClNH3]2+ (en= NH2CH2CH2NH2 is ethylenediammine)
They should exist in two forms, which aremirror imagesof each other. The absolute configuration of [Co(en)3]3+
Chiral; Chirality It is a concept relating to a molecule that is not superimposable on itsmirror image. The one looks like an image in the mirror of the another. These two molecules are considered as chiral molecules. The two chiral molecules have the same physical and chemical properties. Optical Isomer
Optic isomersis also calledenantiomers. Enantiomers are related as non-superimposable mirror images and differ in the direction with which they rotate plane-polarized light. These isomers are refered to as enantiomers or enantiomorphs of each other and their non-superimposable structures are described as being asymmetric.
Because of the prevailing view that optical activity was related to C atoms, Werner prepared a completely chiral inorganic complex (i.e., no C atoms) successfully, to prove that "carbon free inorganic compounds can also exist as mirror-image isomers".
Alfred Werner receivedthe Nobel Prize of Chemistryin 1913 for his coordination theory of transition metal-amine complexes.
Coordination chemistryis the study of compounds formed between metal ions and other neutral or negatively charged molecules. A coordination compoundis the product of a Lewis acid-base reaction in which neutral molecules or anions (called ligands) bond to a central metal atom (or ion) by coordinate bonds.
For example: A complex is Ag(NH3)2+, formed when Ag+ ions are mixed with neutral ammonia molecules. Ag+ + 2 NH3 Ag(NH3)2+ A complex Ag(S2O3)23- is formed between silver ions and negative thiosulfate ions: Ag+ + 2 S2O32- Ag(S2O3)23-
Journal of Coordination Chemistry Editors: Jim D. Atwood, Department of Chemistry, 556 Natural Sciences Complex, North Campus, SUNY University at Buffalo, NY 14260-3000 USAPeter Williams, Centre for Industrial and Process Mineralogy, School of Science, Food & Horticulture, University of Western Sydney, Locked Bag 1797, Penrith South DC, NSW 1797, Australia
Something old and something new, Something borrowed and something blue, Something lacy and something racy, It will definitely be new And it might just be from you.
Structures of coordination compounds can be very complicated, and their names long because the ligands may already have long names. Knowing the rules of nomenclature not only enable you to understand what the complex is, but also let you give appropriate names to them.
The rules are outlined below: 1. In naming the entire complex, the name of the cation is given first and the anion second (just as for sodium chloride), no matter whether the cation or the anion is the complex species. 2. In the complex ion, the name of the ligand or ligands precedes that of the central metal atom. (This procedure is reversed for writing formulae.)
3. Ligand names generally end with 'o' if the ligand is negative ('chloro' for Cl-, 'cyano' for CN-, 'hydrido' for H-). For neutral ligands, their names are not changed ('methylamine' for MeNH2). Special ligand names are as follow: H2O, aqua NH3, ammine (not two m's, amine is for organic compounds) CO, carbonyl NO, nitrosyl
The last "e" in names of negative ions are changed to "o" in names of complexes. Sometimes "ide" is changed to "o". Note the following: Cl-, chloride --> chloro OH-, hydroxide --> hydroxo O2-, oxide --> oxo O22- peroxide, --> peroxo CN-, cyanide --> cyano
bromide (Br-) ----> Bromo nitrite (NO22-) ----> nitrito (M – O bond) nitro (M – N bond) carbonate (CO32-) ----> carbonato oxalate (C2O42-) ----> oxalato sulfate (SO42-) ----> sulfato thioSulfate (S2O32-) ----> thiosulfato
N3-, azide -> axido; NH2-, amide -> amido CO32-, carbonate -> carbonato -ONO2-, nitrate -> nitrato (when bonded through O) -NO3-, nitrate -> nitro (when bonded through N) S2-, sulfide -> sulfido SCN-, thiocyanate -> thiocyanato-S NCS-, thiocyanate -> thiocyanato-N -(CH2-N(CH2COO-)2)2, ethylenediaminetetraacetato (EDTA)
4. A Greek prefix (mono, di, tri, tetra, penta, hexa, etc.) indicates the number of each ligand (mono is usually omitted for a single ligand of a given type). If the name of the ligand itself contains the terms mono, di, tri, for example, triphenylphosphine, then the ligand name is enclosed in parentheses and its number is given with the alternate prefixes bis, tris, tetrakis instead.
For example, Ni(PPh3)2Cl2 is named dichlorobis(triphenylphosphine)nickel(II). Greek prefix: mono-, di- (or bis), tri-, tetra-, penta-, hexa, hepta-, octa-, nona-, (ennea-), deca- etc for 1, 2, 3, ... 10 etc. 5. A Roman numeral or a zero in parentheses is used to indicate the oxidation state of the central metal atom.
6. If the complex ion is negative, the name of the metal ends in 'ATE' for example, ferrate, cuprate, nickelate, cobaltate etc. 7. If more than one ligand is present in the species, then the ligands are named in alphabetical order regardless of the number of each. For example, NH3 (ammine) would be considered an 'a' ligand and come before Cl- (chloro). (This is where the 1971 rules differ from the 1957 rules. Some texts still say that ligands are named in the order: neutral then anionic).
If complexes is an anion, its name ends with –ate appended to either the English or Latin name of the metal. Example: Scandium, Sc = scandate Trtanium, Ti = trtanate vanadium, V = vanadate chromium, Cr = chromate manganese, Mn = manganate iron, Fe = ferrate cobalt, Co = cobaltate nickel, Ni = nickelate copper, Cu = cuprate zinc, Zn = zincate